Telephone-exchange system.



Patented Nov. 17

3 -SHEETSSHEET 1.

Wihwaaao J. L. WRIGHT. TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED MAY 1B, I906.

Patented Nov. 17, 1914.

3 SHEETS-SHEET 2.

galvanic",

J. L. WRIGHT. TELEPHONE EXCHANGE SYSTEM APPLICATION FILED MAY 18, 1906. 1,1 17,297, Patented Nov. 17, 1914.

3 SHEETSSHEET 3.

uvenl'o'c SS A! E T EC.

JOSEPH LANE WRIGHT, 01E WASHINGTON, DISTRICT OF COLUMBIA, ASBIGNOE, B31 MESNE ASSIGNMENTS, T0 FREDERICK C. STEVENS, 0F ATTICA, NEW YQEK.

TELEPHONE-EXCEANGE SYSTEM.

Specification of Letters Patent.

Patented Now. as, rare.

Application filed may 18, 1906. Serial No. 817,458.

tion.

My invention relates to telephone exhange systems and especially to the type known as full automatic, and the object of my invention is the provision of means for reducing the number of contacts and simplifying the switches commonly known as the first and second selector switches or even third selector switches, depending, of course, on the size of the exchange.

Most switches in automatic systems have two motions, either a vertical motion for picking out the desired group and then a rotary motion for picking out an idle contact in this group, or first a rotary motion and then a vertical motion. 1 eliminate this double motion by inserting a switch which I will call a primary selector between the various selector and connector switches. The switches known ordinarily as first and second selector switches, etc., and only containing ten sets of contacts. simply respond to the impulses from a subscrihers sender at the substation and the wipers then come to rest on contacts leading to contacts in the banks of a group or set of primary selector switches. The wipers of the selector switch resting on these contacts star-t the primary selectors rotating to pick out or find the calling selector switch. This operation is repeated throughout the various switches until the connector switch is reached which is thereupon operated and picks out the desired line in the ordinary manner. By cutting down the mechanism of these switches and also the number of contacts, I have simplified them to a large extent, and also make quite a saving in the number of relays required to operate the switch.

Specifically stated, my invention consists in the use of single motion first and second selector switches and by the introduction of primary selector switches which test back to find the calling switch. in the accompanying drawings l have shown the shaft or spindle of these various primary selector switches being rotated by a stepping magnet controlled by the first and second selector switches. Instead of operating them by this method, I may have the various spindles driven in any other desired manner. l consider the method shown preferable as the switches then are only in motion while being actually used. in my invention instead of having the first and second selector switches pick out the desired group and then an idle contact in the group, I have them pick out a contact and then an idle primary selector of the group pick out the contact. In other words, the testing is done in reverse order to that ordinarily used, and this system may properly be called an automatic system employing a back test.

My invention is illustrated in the accompanying drawings wherein- Figure 1 shows a subscribers station with a central otiice equipment, a primary selector switch, and afirst selector switch. Fig; 2 shows a primary selector switch and a second selector switch. Fig. 3 shows a primary selectorswitch and a connector switch.

Referring now to Fig. 1, the subscribers station A is equipped with apparatus usual in common battery installations, consisting of transmitter T, receiver R, hook H, ringers Q, condenser t, and in addition a sending device P for transmitting impulses for operating the switching mechanism at central. The subscribers line terminates in a central office on a line relay L through the normally closed contacts of a cut-0d relay M. When this relay L is energized, it closes the circuit of the vibrating magnet ll) of the primary selector switch which upon'operation causes the s indle Z to rotate. I mount upon the spin le a sufficient number of primary seleclor sets. and provide in conjunction therewith a corresponding number of trunks, to properly handle the maximum number of simultaneous incoming calls. Connective apparatus equal to ten or cent. of the lines is usually found sutiicient, and this some times falls to five. The multiple contacts of the line extensions designed to be engaged by the wipers of the several sets in each group have been shown conventionally opposite the wipers w. u" and 11: but I have not shown the multiple switches, because this would needlessly complicate the drawing. Neither have 1 indicated in the drawings the exact number of lines multiplied into each primary selector switch bank. because this is not fixed, but may be varied at will. The

till

number 01' primary selectors may he more or less than that of the number 0t conductors,- depending upon the eamnt to which the lines are used for calling or called by others. in an exchange serving more than one hundred lines, it is customary to divide them into groups of one hundred, each group being served by ten, more or less, primary selector switches having a common spindle (d it has been found (and this forms no part oi my present invention) that interference between several primary selectors driven b a common motor can be avoided by spacing them apart singularly, or otherwise arranging them on the spindle, assuming the multiples oi the same lines to be verticall above each other, or conversely by arranging the multiples of the lines so they will not be'in vertical columns, and having'all of the switch wipers in line. Such arrangements are recognized by me as forming a part of the prior art, and theretore available in using my 'sys; tem commercially. Another feature which has been known bctore my invention is that of preventing the subscriber from sending impulses before he has become connected with a trunk, The simplest way to avoid this is to speed up the switches, and it has been found practical with a power driven switch to test one hundred contacts in less than three seconds. The time consumed by a subscriber in taking down his receiver, adjusting the same to his ear, and grasping the sending device. is never less than three seconds, and is usually considerably more. However, such means to this end may be provided without all'ecting the present invention. tln the spindle is carried a loose fitting sleeve Z carrying the wipers w, w and to. This sleeve revolves with the s indie by means of the pin 2 which is rigidly attached to a collar 2" fastened to the spindle Z. There is a similar collar a attached to the sleeve Z which has a small hole or perforation in which the pin a normally rests. llhen the double wound magnet G is energized, its armature g lifts the sleeve Z out of engagement with the pin a and the sleeve itself thereupon will cease to rotate, being lrose upon the spindle and held firmly by the upward thrust oi the lever g and friction otthe wipers upon the lower side of the contacts. Battery is supplied to the trunlt wires 5 and 6 and from there to the calling subscriber through the windings oil the two relays S and id. The relay 8 controls the two or lenoids l and E2 the solenoid i through its back contact and the solenoid lE through its front contact. The solenoids or slow acting relays respond readily to quiclr maltes and. brealts oi the contacts in the relay S. ll'hile these relays draw up the cores c and rel-y quickly, they drop back very slowly, so it lollows that when a set of impulses are sent in :lron'i the subscribers station oldestaliases mg the relay S, both solenoids or relays draw up their cores which remain drawn up while the impulses are being transmitted. Between each set of im ulses there follows a momentary closure or the line being due to the act of the subscriber setting up another set or number and during this interval the relay remains energized keeping the solenoid E energized, wile the solenoid E becomes dee'nergized and its core droppin 3 down closes the contact springs s and e sending rotary impulse to the switching, mechanism. The magnet D respondingr to the impulses sent lrom the subscribers station causes the spindle id to rotate. llhis spindle carries wipers w, ooh w, to 'w and w. These wipers pass over a set of contacts leading to a primary selector switch which is connected to trunlr wires leading to a second selector switch. 'llhere are only ten sets of these contacts in the hanlrs ot the first selector switch Id, this being the only number required, lortinstead oil the first selector switch itselll pichin out anidle trunk, it simply step it around to the first numeral oil the desired line and thereafter primary selector switch attached to second selector switch steps around its wipers and piclrs out the contacts upon which the wipers oi the first selector switch rest.- llt will be seen from this method that instead oi the first selector switch picking out an idle trunlr, l have an idle trunk piclr out the first selector switch. l introduce this primary selector between each selector and connector switch and by doing so cut down the number oi contacts in each switch, and instead of having a selector switch make two motions such as would be required to pick out the desired row and then piclr out an idle contact, in my system ll simply have to mahe a rotary moll tlon over ten sets of contacts. Referring to the wipers mounted ontthe sleeve Zl, l have the wiper to wipe over the contacts while revolving so as to pick out the calling line. The wipers w and to while sweeping over the contacts, do not touch them until the calling line is actually picked out and when this'happens the magnet G becomes energized, and lifting the sleeve, brings the wipers w and w into engagement with the desired line. ll malre this arrangement so as to prevent annoying cliclrs to the various subscribers whose lines may be busy.

Referring now to Fig. 2, the primary se let-tor switch is the saline as that already described in ll ig. l with the exception that l have added a release or holding magnet W. The armature wot this magnet engages the tooth .2 when the sleeve Z is lifted up by the magnet G and holds it in that position. in this switch the trunk wipers w and w while sweeping over the contacts do not engage them until the sleeve E has been lifted by the magnet G. The second selector till lldti llllli tumor switch is the same as the first selector with the exception that I have added a relay S to the trunk wire 11 for operating the 1'0? tary magnet D Referring now to Fig. 3, the primary selector switch is the same as already described in the foregoing figures. The connector switch is a two-way switch, that is to say, it has both a vertical and a rotary .movement. In this present system, I make the rotary movement first. The rotary magnet D is controlled by the relay S which s connected to the-trunk wire 15 through the normally closed contacts ofthe relay S. The relay S is connected to the trunk wire 16 through the normally closed contacts of the relay 5. The first impulse or working of this relay S closes the circuit of the vertical magnet l) by the following path: battery, 78, 92, D 91 as, m 93, a, a, ground. This causes the spindle Z to take one step. This step removes the rotary magnet D from under the control of the relay S and in its place connects the vertical magnet D This transfer takes place through the contacts a w and rat. The second set of impulses coming in afiecting the relay S now operates the magnet D cans ing the spindle to step up vertically. The first vertical movement oi the spindle after the false movement caused by the relay S" as already described, operates the contact springer, e and m The operation of these springs removes the magnet 11) from under control of the relay S and in its place connects the bridge relay d. The second rotary impulse now coming in closes the circuit of this relay d which thereupon locks itself, completing the trunl: wires 1'3 and 18 respectively through to the trunk wipers co and ac. The operating of this relay also disconnects the vertical magnet D and in its place connects the ringing relay K. The.

release magnet ll has a ll-shapedarmature, one arm of? which normally engages the vertical teeth, while the other arm engages the rotary teeth of the spindle Z. The cnergia ing of this magnet allows the spindle to drop and then rotate, assuming its normal position. Battery is supplied to the called subscriber through the retardation coil .l and the relay S The relay S becoming energized when the called subscriber answers, disconnects the relays S and S and short-circuits the condensers and C -respectively. This is simply done for an: purposes as it removes the bridges and condensers from the line.

The operation ct my system is as follows: The subscriber at station A, desiring to make a call, removes his receiver. The line circuit being thus closed causes the rel'ay L tobecome energized, closing the cir cult of the magnet D. T heoperation of this memoir. causes the spindle Z to rotate. The

the magnet wiper w of the first set making connection with the bus contact, closes the circuit of by the-following path: battery B, 25, 24, 1, l, 45, w, one winding of the magnet G to ground. The operating of the magnet b lifts the sleeve Z bringing the wipers. w and w in connection with their contacts, closing the circuit oithe cut-oil relay in series with the relay S. The energizing of the relay M disconnects the relay L, removing battery from the busy contact upon which the wiper w rests. The circuit of the magnet D is also open and the spindle a will cease to rotate unless some other party happens to be calling in at that instant, in which case the circuit of the magnet D would be inept closed by some other line relay. The relay ti becoming energized by current flowing through the circuit B, 25, 26, S, 6, 4., 2, substation, 1, 3, 5, S and ground, closes the circuit B, 25, 26, e, 28, a, 29, E and ground of the solenoid E which in t holds the relay (l energized through its second winding by the following path: battery ll, 25, 36, 4/4, e, a, all G to ground. The calling subscriber is now connected to the first se-= lector. switch and sets his number wheel to the desired number. This wheel in rnnning down makes and breaks the contacts p and p which operates the relay S. The operation oi this relay closes the circuit oi the solenoid E which draws up its coreand remains energized while these impulses are being so sent, The relay S being responsive L 7", ,f to ground. The magnet l) operating causes the spindle 22 carrying the wipers to rotate a number of times corresponding to the impulses sent. The calling subscriber is now connected to contacts in the banks oi the primary selector switches and it only remains for an idle primary selector switch to pick out the first selector switch.

This act is brought about as follows: the

wiper er closes the circuit of the vibrating magnet D by the following path: battery B, 36, f f 34., @22 ll, D to ground. This magnet, starting up, causes the spindle Z carrying the wipers belonging to sets of primary selector switches to rotate. The wipers oi the first set coming in connection with the busy contacts hare the circuit of the magnet ll closed by the following path: battery B, 36, F, f, 38.. te lit, w, 51, G to ground. The operation oi" this magnet lifts the sleeve Z and brings the trunk wipers into connection with the trunk contact. and at the same time the circuit oi the relay l Fig. l, is closed through the wiper 20. thus disconnecting the magnet G. The sleeve 2 is kept in position by the arma- Mill 35o secmnd Saleem? SWluCh 5110,61

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umor allows the sleeve Z, carrying the wipers, to assume its normal position, disconnecting the cut off relay M and again placing the line relay L under control of the calling subscriber.

Having thus described my invention what I claim and desire to secure by Letters Patent of the United States is:

1. In a telephone exchange system, the combination with a plurality of subscribers stations having impulse senders and a central station comprising groups of impulse receiving switching devices, andinterposed switching devices between the lines and the first group of impulse actuated switches, and between each successive group of such switches, each interposed device being adapted to test for a calling unit in a preceding group and connect the same to its associated unit in its own group.

2. In a telephone exchange system, the combination with a plurality of subscribers? stations and a central station, of lines interconnecting them, means to close the respective lines in calling to cause primary impulses, sending devices to produce successive impulses, switching mechanism at the central station for receiving the primary impulses, groups oi switching'mechanism for receiving successive impulses, and switches interposed between the lines and the first group of impulse actuated'switchcs, and similar test switches associated with each successive group, said interposed testing switches beingirresponsive to any impulses received ailter the first or starting impulse.

3. ln a tele hone exchange system, the

combination with a plurality of subcribers stations having impulse senders and a central' station, oil a trunlr line there at, a first selector switch therein, a second selector switch therein, a connector switch for picking out the wanted subscriber, and internosed switches adapted successively to test tor and interconnect the impulse actuated selectors to the connector switch.

Y 4. in a telephone exchange system, the combination with a plurality of subscribers stations having impulse senders and a central station, of connecting therein, a first selector switch therein, a second selector switch therein, a connector switch for picking out the wanted subscriber, a switch between the trunks and lines, a testing switch between the first and second selector switches, and a testing switch between the second selector switch and the connector switch, all of said testing switches being irresponsive to the impulses which adect the before mentioned sw tches.

5. a telephone exchange system, the combination with a plurality of subscribers stations having impulse senders, and a central station, of impulse actuated selecting devices, line testi and selecting means, and a plurality of associated but independently operable switches interposed between the impulse actuated switches for testing pre ceding links in succession. and interconnecting them.

6. In a tele hone exchange system, theoombination o a subscribers station having an impulse sender, switching means at the central station having vertical and rotary operating mechaiuism, means controlling the vertical impulses to said switching means adapted when released to send a false impulse thereto, means controlled by said false impulse-for operating the switch, in a vertical direction, and means controlled by the spindle of the switch whery the rotary operating mmns is rendered inoperative and the vertical switch operating means is thrown into action.

7. In a telephone exchange system, a pin-- rality of line circuits, with two-motion-aut omatic switches for interconnecting them,

each line havinggmeans asccciated with it to send impulses Ior shooting the two motions of the switch, each switch comprising a spindle adapted for vertical and 'rotarv movement, means for .inoving'the switch verth cally, means for rotating the switch, and means controlled by the spindle thereof for rendering one of said means inoperative and the other operative.

8. ln a telephone exchange system, a plurality of line circuits provided with means for sending impulses, automatic switches tor interconnecting the lines, each switch having separate means, impulse controlled or operating it in arotery and in a vertical direction, and means controlled bv the spindle of the switch for rendering either one of said switch operating nieansinoperable and the other operable.

9. ln an automatic telephone system, the combination with a subscribers station having a vertical and rotary impulse sender and a central station, of switchin mechanism for connecting the subscriber with the wanted line, means controlled by the vertical impulses for rotating the switch, means controlled by the vertical impulses for moving the switch in a vertical direction, means operated intermediate or the before mentioned steps by the rotary impulse for giving the spindle oi the switch a false vertical movement, and means under control of the spindle for transferring the operation oil the rotary controlling means to the vertical controlling means.

10. In a telephone exchange system, subscribers substations provided with impulse sending devices, a central ofice, a plurality of automatic switches located at said central ofice and operated by impulses from said sending devices for interconnecting said subsauna interposed witch ng de ic s irrelllii 

